Matt Sealey writes: > Book I compatible PowerPC's have had a "no-executable" bit in > the page protection flags since the dark ages.. see page 7-38 > and 7-39 of the 'Programming Environments Manual for 32-Bit > Microprocessors'.. this document predates even the G3.
What are you referring to? I have a copy of the PEM from pre-G3 days, and a copy that I downloaded just now, and neither of them have an N bit in the PTE (and yes I just looked carefully through pages 7-38 and 7-39). There is an N bit in the segment register format, and that's what Albert is using. > As far as the documentation goes, you can make the page > readable and writable to the LSU, but the N bit causes the > instruction fetch to cause a machine check. That's pretty > "not-executable" to me at least :) A machine check is nasty, because it may not be recoverable... Paul. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
